diff --git a/spec/util/UnsubscriptionError-spec.ts b/spec/util/UnsubscriptionError-spec.ts
index dad0143705f..f2f1db9b270 100644
--- a/spec/util/UnsubscriptionError-spec.ts
+++ b/spec/util/UnsubscriptionError-spec.ts
@@ -19,9 +19,7 @@ describe('UnsubscriptionError', () => {
       subscription.unsubscribe();
     } catch (err) {
       expect(err instanceof UnsubscriptionError).to.equal(true);
-      expect(err.message).to.equal(`2 errors occurred during unsubscription:
-  1) ${err1}
-  2) ${err2}`);
+      expect(err.errors).to.deep.equal([err1, err2]);
       expect(err.name).to.equal('UnsubscriptionError');
     }
   });
diff --git a/src/observable/dom/AjaxObservable.ts b/src/observable/dom/AjaxObservable.ts
index b8fc058a7c7..427d1f1eee0 100644
--- a/src/observable/dom/AjaxObservable.ts
+++ b/src/observable/dom/AjaxObservable.ts
@@ -452,6 +452,9 @@ export class AjaxError extends Error {
     this.status = xhr.status;
     this.responseType = xhr.responseType || request.responseType;
     this.response = parseXhrResponse(this.responseType, xhr);
+
+    this.name = 'AjaxError';
+    (Object as any).setPrototypeOf(this, AjaxError.prototype);
   }
 }
 
@@ -480,5 +483,6 @@ function parseXhrResponse(responseType: string, xhr: XMLHttpRequest) {
 export class AjaxTimeoutError extends AjaxError {
   constructor(xhr: XMLHttpRequest, request: AjaxRequest) {
     super('ajax timeout', xhr, request);
+    (Object as any).setPrototypeOf(this, AjaxTimeoutError.prototype);
   }
 }
diff --git a/src/util/ArgumentOutOfRangeError.ts b/src/util/ArgumentOutOfRangeError.ts
index 4384a2b465c..d3155f3361e 100644
--- a/src/util/ArgumentOutOfRangeError.ts
+++ b/src/util/ArgumentOutOfRangeError.ts
@@ -10,9 +10,8 @@
  */
 export class ArgumentOutOfRangeError extends Error {
   constructor() {
-    const err: any = super('argument out of range');
-    (<any> this).name = err.name = 'ArgumentOutOfRangeError';
-    (<any> this).stack = err.stack;
-    (<any> this).message = err.message;
+    super('argument out of range');
+    this.name = 'ArgumentOutOfRangeError';
+    (Object as any).setPrototypeOf(this, ArgumentOutOfRangeError.prototype);
   }
 }
diff --git a/src/util/EmptyError.ts b/src/util/EmptyError.ts
index d1184ab189f..fbfe7bf88dd 100644
--- a/src/util/EmptyError.ts
+++ b/src/util/EmptyError.ts
@@ -10,9 +10,8 @@
  */
 export class EmptyError extends Error {
   constructor() {
-    const err: any = super('no elements in sequence');
-    (<any> this).name = err.name = 'EmptyError';
-    (<any> this).stack = err.stack;
-    (<any> this).message = err.message;
+    super('no elements in sequence');
+    this.name = 'EmptyError';
+    (Object as any).setPrototypeOf(this, EmptyError.prototype);
   }
 }
diff --git a/src/util/ObjectUnsubscribedError.ts b/src/util/ObjectUnsubscribedError.ts
index 460a31029a6..fb005457e7d 100644
--- a/src/util/ObjectUnsubscribedError.ts
+++ b/src/util/ObjectUnsubscribedError.ts
@@ -9,9 +9,8 @@
  */
 export class ObjectUnsubscribedError extends Error {
   constructor() {
-    const err: any = super('object unsubscribed');
-    (<any> this).name = err.name = 'ObjectUnsubscribedError';
-    (<any> this).stack = err.stack;
-    (<any> this).message = err.message;
+    super('object unsubscribed');
+    this.name = 'ObjectUnsubscribedError';
+    (Object as any).setPrototypeOf(this, ObjectUnsubscribedError.prototype);
   }
 }
diff --git a/src/util/TimeoutError.ts b/src/util/TimeoutError.ts
index c68adffac46..506249e94d6 100644
--- a/src/util/TimeoutError.ts
+++ b/src/util/TimeoutError.ts
@@ -7,9 +7,8 @@
  */
 export class TimeoutError extends Error {
   constructor() {
-    const err: any = super('Timeout has occurred');
-    (<any> this).name = err.name = 'TimeoutError';
-    (<any> this).stack = err.stack;
-    (<any> this).message = err.message;
+    super('Timeout has occurred');
+
+    (Object as any).setPrototypeOf(this, TimeoutError.prototype);
   }
 }
diff --git a/src/util/UnsubscriptionError.ts b/src/util/UnsubscriptionError.ts
index 412164ed766..47999fc1e08 100644
--- a/src/util/UnsubscriptionError.ts
+++ b/src/util/UnsubscriptionError.ts
@@ -4,12 +4,10 @@
  */
 export class UnsubscriptionError extends Error {
   constructor(public errors: any[]) {
-    super();
-    const err: any = Error.call(this, errors ?
+    super(errors ?
       `${errors.length} errors occurred during unsubscription:
   ${errors.map((err, i) => `${i + 1}) ${err.toString()}`).join('\n  ')}` : '');
-    (<any> this).name = err.name = 'UnsubscriptionError';
-    (<any> this).stack = err.stack;
-    (<any> this).message = err.message;
+    this.name = 'UnsubscriptionError';
+    (Object as any).setPrototypeOf(this, UnsubscriptionError.prototype);
   }
 }